A magnetoresistive effect element is used as a magnetic head (a reproducing element head) for an HDD (Hard Disk Drive) or the like. In order to reduce influence of an external magnetic field, it is common to dispose a magnetoresistive effect element between magnetic shields in the magnetic head of the HDD, and a reproducing resolution is prescribed by an interval between the magnetic shields.
In the HDD, improvement of the reproducing resolution is desired in order for improvement of a reproducing density. However, in a conventional magnetic head, shortening an interval between magnetic shields is difficult due to a structure, so that it has become difficult to improve the recording density.
Thus, in order to heighten a resolution, a magnetic head of a differential output type is suggested. The magnetic head of the differential output type has two free layers which react to a signal magnetic field, and a reproducing resolution is prescribed by a free layer interval. In other words, compared with the conventional magnetic head, heightening of a resolution mainly in a line recording density direction (BPI direction) is more practicable.
However, in the magnetic head of the differential output type, it is not necessarily easy to heighten a resolution in a track width direction (TPI direction).